As integration levels in integrated circuits increase, packaging has become the focus of the microelectronics industry. A redistribution layer (RDL) technology is a part of the advanced packaging technologies, and has important applications in chip packaging with a high I/O density.
In the redistribution layer (RDL) technology, original bonding positions of I/O pads designed in an IC circuit are changed by a wafer-level metallic wiring process and a bumping process, so that different forms of packaging can be applied to the IC circuit. The wafer-level metallic wiring process includes: forming an insulating protective layer on the IC circuit; forming a new wiring pattern by exposure and development processes, and forming new metallic wires by an electric plating method to connect the original aluminum pads and new bumps or gold pads. Correspondingly, the wires in the IC circuit are redistributed. The redistributed metallic wires are mainly made of an electroplated copper. Copper has advantages of a low resistance, a high heat dissipation, and a low cost, and is the best choice for high-current and high-power devices.
The RDL technology can change the original I/O design, increase additional values of the original design, increase spaces between the I/O pads and provide bumps with bigger areas. As such, strains between the substrate and the device are reduced, and reliabilities of the devices are improved.
However, performance of semiconductor structures formed by the redistribution layer technology still needs to be improved. The disclosed devices and methods are directed to at least partially alleviate one or more problems set forth above and to solve other problems in the art.